Vandersteen Cinema loudspeaker system (SGHT Review) Sidebar 2: Measurements
Logistical problems prevented measurement of the Vandersteen VCC-1 two-way center-channel loudspeaker. The Vandersteen 3A's sensitivity is a little lower than average at an estimated 85dB/W/m (B-weighted). A minimum amplifier power of 50Wpc would be a good idea. Its impedance remains below 6 ohms for much of the range, and dips under 3 ohms at 35Hz. The 3A is a moderately demanding load, though the phase angle is usefully low.
Other than a small suckout at just below 1kHz and some response ripples in the low treble, which would appear to be due to reflections from the cabinet top and its support rods, the 3A's on-axis response is commendably flat as long as the listener is on or below the tweeter axis (39" from the floor). This means that it would be better to err on the side of a slightly too-great cabinet tilt-back than not enough. The tone controls provide a moderate degree of cut or boost of up to 3dB in the presence region (1-4kHz) and high treble (above 7kHz).
The 1kHz response notch deepens at extreme off-axis angles. The overall dispersion through the midrange and top end—making allowances for the small ripples caused by cabinet reflections—is otherwise excellent.
The impulse and step responses on the tweeter axis reveal an excellent time-coherent presentation. The cumulative spectral-decay, or waterfall plot, indicates some delayed energy in the midrange, but the high-frequency response is very clean.—John Atkinson